Methods for colorizing a display device mainly employ a method based upon spatial division and a method based upon time division. Further, there are also display devices that use a combination of both of these methods. Examples of colorization using spatial division are a delta-shaped spatial array of phosphors of a plurality of colors in a CRT and a spatial array of color filters in a liquid crystal display. Colorization using time division usually is referred to as a “color field sequential technology”. With a color field sequential method, a color display is realized not by dividing one pixel spatially but by varying color displayed on a time-wise basis.
Since the color field sequential method does not divide pixels spatially, it excels in terms of aperture ratio and readily lends itself to microfabrication. In addition, since the necessary number of wiring traces is small, the scale of the driving circuit can be reduced and packaging facilitated. In particular, in a case where color conversion efficiency is not high in spatial color generation, e.g., in a case where the amount of absorption of light is large, which is a result when a liquid crystal display uses color filters, using the color field sequential method makes it possible to raise the efficiency of utilization of light and reduces power consumption.
An example of a liquid crystal display device that employs the color field sequential method is disclosed in Patent Document 1. This liquid crystal display device has a display unit and a driving unit, in which the color of a monochromatic image displayed is any one of the three primary colors, and the driving unit causes a monochromatic image to be displayed on the display unit in accordance with a periodic array in which an array of even-numbered monochromatic images is adopted as one unit. FIG. 13 illustrates the relationship between driving voltage and time. Time is plotted along the horizontal axis and voltage along the vertical axis. Voltage is applied in the order of the colors R, G, B, G in one frame 102. By adopting such an arrangement, the colors R, G, B always repeat at the same polarity. As a result, even in a case where a DC voltage component VDC has been superimposed upon the voltage waveform, as illustrated in FIG. 13, the influence of VDC always appears equally in any frame and it is possible to greatly reduce the difference between absolute values of driving voltage produced by a voltage polarity reversal in every frame interval. This makes it possible to obtain a flicker-free high-quality display.
As related art, Patent Document 2 describes an electro-optic device that makes it possible to increase the number of expressible gray levels and improve response in a case where a display is presented using an electro-optic substance having a slow optical response, as in the case of liquid crystal.
[Patent Document 1]
JP Patent Kokai Publication No. JP-P2001-255506A
[Patent Document 2]
JP Patent Kokai Publication No. JP-P2006-301563A